In general, stereoscopic display devices may be classified into a glasses type and a non-glasses type. Most large stereoscopic display devices employ a glasses type. In a stereoscopic display device, light for a left-eye image and light for a right-eye image are emitted in different polarization states and, in glasses worn by a viewer, the light for a left-eye image is incident only on the left eye and the light for a right-eye image is incident only on the right eye, thereby enabling the viewer to feel a stereoscopic sense.
However, in the stereoscopic display device, it is difficult to accurately emit the light for a left-eye image and the light for a right-eye image in preset different polarization states, or it is difficult to manufacture a stereoscopic display device that is capable of accurately emitting the light for a left-eye image and the light for a right-eye image in preset different polarization states.